On Tue, Apr 05, 2022 at 03:16:07PM +0200, Geert Uytterhoeven wrote:
On Tue, Apr 5, 2022 at 1:33 PM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
From: Sean Young sean@mess.org
commit 5ad05ecad4326ddaa26a83ba2233a67be24c1aaa upstream.
Calling udelay for than 1000us does not always yield the correct results.
Cc: stable@vger.kernel.org Reported-by: Михаил vrserver1@gmail.com Signed-off-by: Sean Young sean@mess.org Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/media/rc/gpio-ir-tx.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-)
--- a/drivers/media/rc/gpio-ir-tx.c +++ b/drivers/media/rc/gpio-ir-tx.c @@ -48,11 +48,29 @@ static int gpio_ir_tx_set_carrier(struct return 0; }
+static void delay_until(ktime_t until) +{
/** delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on* m68k ndelay(s64) does not compile; so use s32 rather than s64.*/s32 delta;while (true) {delta = ktime_us_delta(until, ktime_get());if (delta <= 0)return;/* udelay more than 1ms may not work */delta = min(delta, 1000);udelay(delta);}Yeah, that's why we have mdelay(), which loops around udelay() if no arch-specific implementation is provided.
That is a good point. That doesn't make this patch incorrect, just a bit ugly. Can this patch be merged as-is please, and I'll write an patch upstream that simplifies the code.
Thanks Sean
+}
static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf, uint count) { ktime_t edge;
s32 delta; int i; local_irq_disable();@@ -63,9 +81,7 @@ static void gpio_ir_tx_unmodulated(struc gpiod_set_value(gpio_ir->gpio, !(i % 2));
edge = ktime_add_us(edge, txbuf[i]);
delta = ktime_us_delta(edge, ktime_get());if (delta > 0)udelay(delta);
delay_until(edge); } gpiod_set_value(gpio_ir->gpio, 0);@@ -97,9 +113,7 @@ static void gpio_ir_tx_modulated(struct if (i % 2) { // space edge = ktime_add_us(edge, txbuf[i]);
delta = ktime_us_delta(edge, ktime_get());if (delta > 0)udelay(delta);
delay_until(edge); } else { // pulse ktime_t last = ktime_add_us(edge, txbuf[i]);Gr{oetje,eeting}s,
Geert-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds